The present invention relates generally to medical devices and methods. More particularly, the present invention relates to methods and apparatus for removing veins from surrounding connective tissue.
Various techniques have been developed to treat varicose veins. In simple cases, elevation of the legs and compression stockings may be sufficient therapy to mitigate the progression of the varicose veins. An alternative therapy includes “sclerotherapy.” In the procedure, the diseased veins are injected with a sclerosing solution, such as sodium tetradecyl sulfate, along the tract of the varicose vein. Typically, multiple injections are administered during a treatment session. The sclerosing solution causes subsequent inflammation and damage to the endothelial cell lining of the vein. This damage and contraction in conjunction with post-procedural external compression results in localized occlusion or contraction of the vessel which forces rerouting of the blood through other conduits and in ideal circumstances causes the vein to become a fibrin cord which is resorbed over time. With this therapy, patients typically require two or more treatment sessions in order to satisfactorily alleviate the varicose veins. However, typically the technique does not provide a permanent or complete solution with varicose veins reoccurring over time. Consequently, sclerotherapy is often combined with a more invasive operation such as ligation and/or stripping of the saphenous vein. In additionally, sclerotherapy is not without the potential for complication. These can include the potential for browning splotches or bruising of the skin, formation of blood clots in the veins, inflammation, adverse allergic reactions, ulceration, phlebitis, anaphylactic overdose, ischemia, skin or fat necrosis, and peripheral neuropathy.
In another technique, varicose veins are removed by “stab-avulsion phlebectomy” with small surgical hooks. In this technique, the varicose veins are removed and/or ligated through a series of separate small skin incisions. These incisions are made along the vein path and the vessel is exteriorized using small hooks and forceps. Once exteriorized, the loop is put under traction, divided, and both ends avulsed separately. When a loop of a larger varicose vein is exteriorized, it is pulled with rocking motions. These alternating traction movements permit detachment from perivenous tissue as well as allow for further identification of the vein path. During this procedure compression is applied at the incision locations to promote hemostasis. With this therapy patients typically only require one treatment session. However, in many cases dependent on the skill of the surgeon and on the extent of the varicose anatomy, the procedures is very time intensive and can take between 2–3 hours to complete. In addition, the procedure also requires multiple incisions and in many cases the veins tend to fragment into small segments while being avulsed making it difficult to entirely remove the targeted veins. Finally, patients typically experience ecchymosis (bruising) for up to four weeks post-operatively and in more extreme instances can experience complications including infection, deep or superficial thrombophlebitis, lymphorrhea, paresthesia and hematoma.
In addition to these procedures which are in clinical use, it has been proposed in the patent and medical literature to use intravenous devices for invaginating and stripping vericose veins. For example, U.S. Pat. No. 6,030,396, describes a device which is introduced through a venous penetration and advanced to a distal location within the venous lumen. The lumen is surgically opened at the distal location and the vein severed. The severed end of the vein is then sutured to the device, and the device withdrawn proximally to evert and remove the vein. Although a promising procedure, the need to surgically open the proximal venous location and suture the vein to the device is a drawback of the procedure. An analogous procedure for removing varicose veins using an endoscope is described in published PCT Application WO 00/45691. In that patent application, an endoscope having several channels is introduced through a penetration into the venous lumen, preferably over a guidewire. While visualizing the luminal wall, a balloon is inflated and facilitates frictional engagement of the vein segment prior to removal. WO 94/21177 describes use of a device with exposed barbs for endoluminal introduction and capture of a vein prior to avulsion and removal.
In view of the above, it would be desirable to provide improved apparatus and methods for venous removal, particularly for the removal of vericose veins in a minimally invasive. It would be particularly useful to provide apparatus and methods which may be performed endovascularly, i.e., through the venous lumen and which simplify capture and retraction of a distal end of the vein to remove, and optionally without the need for visualization, particularly endoscopic visualization, during the procedure. Such procedures should preferably require only a single tissue penetration to permit introduction of the removal apparatus, while providing for simplified and improved methods for capturing and avulsing a distal end of the vein remote from the introductory point. At least some of these objectives will be met by the inventions described hereinafter.
Relevant U.S. Patents include U.S. Pat. Nos. 6,077,289; 6,030,396; 5,893,858; 5,011,489; 4,517,965; 3,764,427; 3,568,677; and 3,508,553. Relevant PCT Publications include WO 01/37739; WO 00/45691; WO 99/17664; and WO 94/21177. Descriptions of phlebectomy and related procedures are found in Ambulatory Phlebectomy, Ricci and Georgiev with Goldman, pp 67–126 Mosby—Year book, Inc., St. Louis, Mo. and Vein Diagnosis and Treatment: A Comprehensive Approach, Weiss et al. Eds., McGraw Hill Medical Publishing Division, New York 2001, Chapter 22, pp 197-210.